any change in the refractive index of a laser active medium can lead to serious degradation of beam quality, laser beam modes, laser performance and variation in the intensity distribution. alteration in the refractive index of laser active medium is especially notable in high power lasers. it is clear that in the laser beam production, the pumping agent induces a great amount of heat which...

the aim of this paper is eliminating cr(vi) by natural hap. hap is a inexpensive material which is used from bovine critical bone ash in order to remove heavy metal ions like cr(vi). some experiments in different ph are performed (ph=2,3,7). maximum adsorption was appeared at ph=2, dosage=0.3 gr, c0=10 mg/l. cr(vi) removal depends on ph value and initial amount of cr(vi) result of experiments w...

a significant problem in multicarrier communication systems is the necessity to reduce the value of papr (peak-to-average power ratio) of transmitting signal. in this thesis we study the effect of the system parameters such as coding and modulation types on papr and ultimate ber in a mc-cdma system. in this study we consider fading channel as well as the nonlinearity of transmitter’s amplifier ...

cultural iran is a scope that is more extended than the political territories of iran as a political unit. this concept means that cultural geography(mehdi moghanlo-1383-1) of iran is greater than its political geography which, according to history, has a long history extending west-east from kandahar to the euphrates and north-south from the persian gulf to the caucasus including transoxiana a...

one of the most important factors in study of project’s , is the study of environmental opportunities factors the permanent study of environmental opportunity factors . the study of permanent environmental changing and knowing golden threats’ cooperate with possible threats and at the result in structure forming and future skeleton of organization has a vital effects . the petrochemical industr...

on this project we try to calculated power of hydrogen on dycarbonil compound in different ways ; the first way is shoster way , for sain power of hydrogen notice the different power between central conforms on it and main conform that’s didn’t have hydrogen joint . or in other way different of energy between open and close form. second way, is average way? this is for way that studied conf...

abstract the aim of this study was threefold: (1) to investigate the relationship between knowledge of semantic prosody and efl learners general language proficiency; (2) to examine the relationship between qualitative as well as quantitative knowledge of words, and (3) to compare the performance of efl learner on receptive and productive measures of semantic prosody. the study is based on a...

abstract lexical knowledge of complex english words is an important part of language skills and crucial for fluent language use (nation, 2001). the present study, thus, was an attempt to assess the role of morphological decomposition awareness as a vocabulary learning strategy on learners’ productive and receptive recall and recognition of complex english words. so 90 sophomores (female and ma...

as the canon is shaped by white male standards rewriting the canonical works of literature is one of the ways through which postcolonial writers subvert the authority of the masters. writing in the language of the masters the colonized writers use the very suppressive tool in the hands of the masters i.e. their language to question the validity of their norms. regarded by most critics to be the...

the present research was conducted to accomplish two purposes. firstly, it aimed to explore and describe schematic structure or what halliday and hassan (1989, p.64) have called “generic structure potential” (gsp) of american english, iranian persian and iranian english newspaper editorials within systemic functional linguistics. secondly, a quantitative cross-comparison was made to investigate...